Senior US defence officials said trailers and vehicles carrying rocket propellant were in place at North Korea's coastal launch site and that fuelling had begun.

A US counterproliferation official said the fuelling process could take 'up to a few days.' A senior US intelligence official told The Associated Press that Pyongyang was on track for a projected Saturday launch. American officials spoke on condition of anonymity to discuss intelligence issues.

At the G-20 summit in London, Obama and South Korean President Lee Myung Bak issued a statement agreeing on 'a stern, united response from the international community if North Korea launches a long-range rocket.' State Department spokesman Robert Wood would not talk about the US intelligence reports, but he repeated earlier warnings for the North Koreans not to take any 'provocative' actions.

Japan's ambassador to the United Nations said his country will request an emergency session of the Security Council if North Korea goes ahead with the launch. Yukio Takasu said he raised the possibility during private council talks Thursday. Mr Takasu and other council diplomats say they anticipate a possible emergency session as early as this weekend.

Chinese President Hu Jintao urged Japan to handle calmly the expected firing of a rocket by North Korea over Japanese territory, although he says Beijing is working to avert the launch. Mr Hu made the comment in a meeting late Thursday with Japan's prime minister, Taro Aso, on the sidelines of the G20 meeting, said Osamu Sakashita, Mr Aso's deputy cabinet secretary for public relations.

China says it is trying in various ways to dissuade Pyongyang from conducting the communications satellite launch that is widely believed to be a test for a long-range missile.

North Korea heightened its militarist rhetoric toward the United States, Japan and South Korea on Thursday, threatening retaliation for any attempt to shoot down the rocket. Quoting an unidentified North Korean general, the North Korean Central News Agency said Japan would be struck with a 'thunderbolt of fire' if it attempts to intercept the multistage rocket.

The news service also issued a veiled threat against American warships moving in position to monitor the launch, saying: 'The United States should immediately withdraw armed forces deployed if it does not want to receive damage.'

Some US lawmakers are urging Obama to shoot down the rocket if it should endanger the United States or its allies. Defence Secretary Robert Gates said during a weekend TV interview that the United States had no plan to intercept the rocket, although it might consider the move if an 'aberrant missile' were headed to Hawaii 'or something like that'. -- AP